Drug Penetration Enhancement Techniques in Transdermal Drug Delivery System: A Review

Transdermal Drug Delivery System (TDDS) is described as a self-contained or discrete dosage form that is applied to the intact skin. This rout of drug administration of drugs through the skin for therapeutic use is an alternative approach to oral, intravascular, subcutaneous, and transmucosal routes. The delivery of drugs through the skin to the systemic circulation provides a convenient route of administration for a variety of clinical indications. Transdermal Drug Delivery System allows continuous drug administration, use of drugs with short biological half lives, avoids increases hepatic first pass elimination and rapid termination of medication by removing the transdermal drug delivery system from the skin. Various transdermal technologies may be applied for different categories of pharmaceuticals used for the treatment of disorders of the skin or for systemic effects to treat diseases of other organs. Several transdermal products and applications include hormone replacement therapy, contraception, pain management, angina pectoris, smoking cessation, and neurological disorders such as Parkinson's disease. The most commonly used transdermal system is the skin patch using various types of technologies. Stratum corneum is the outermost layer of the skin and it is the main barrier layer for permeation of drug in transdermal delivery of drugs. So, to circumvent the barrier properties of stratum corneum and to increase the flux of drug through skin membrane various penetration enhancement techniques are used in transdermal drug delivery system. The review presents different physical and chemical methods in penetration enhancement approaches and to optimize the transdermal delivery system.